A plant's traits may be controlled through a number of cellular processes. One important way to manipulate that control is through transcription factors—proteins that influence the expression of a particular gene or sets of genes. Because transcription factors are key controlling elements of biological pathways, altering the expression levels of one or more transcription factors can change entire biological pathways in an organism. Strategies for manipulating a plant's biochemical, developmental, or phenotypic characteristics by altering a transcription factor expression can result in plants and crops with new and/or improved commercially valuable properties, including traits that improve yield or survival and yield during periods of abiotic stress, improve shade tolerance, or alter a plant's sensing of its carbon/nitrogen balance.
We have identified numerous polynucleotides encoding transcription factors, functionally related sequences listed in the Sequence Listing, and structurally and functionally similar sequences, developed numerous transgenic plants using these polynucleotides, and analyzed the plants for their tolerance to shade, drought stress, and altered carbon-nitrogen balance (C/N) sensing. In so doing, we have identified important polynucleotide and polypeptide sequences for producing commercially valuable plants and crops as well as the methods for making them and using them. The present invention thus relates to methods and compositions for producing transgenic plants with improved tolerance to drought and other abiotic stresses, with altered C/N sensing, and/or with improved tolerance to shade. This provides significant value in that the plants may thrive in hostile environments where low nutrient, light, or water availability limits or prevents growth of non-transgenic plants. Other aspects and embodiments of the invention are described below and can be derived from the teachings of this disclosure as a whole.